1. Field of the Invention
This invention relates generally to the high pressure/high temperature (BP/HT) process for making polycrystalline diamond and cubic boron nitride cutting elements. More particularly, the invention relates to certain modifications in the HP/HT process which can result in increased efficiency in the production of small cutting elements having improved characteristics.
2. Description of the Prior Art
A cutting element of the type described is a polycrystalline mass of abrasive particles (e.g. diamond and cubic boron nitride) bonded together to form an integral, tough, coherent, high-strength mass. This mass is bonded to a substrate material, such as cemented metal carbide generally selected from the group consisting of tungsten carbide, titanium carbide, tantalum carbide and mixtures thereof with metal bonding material generally selected from the group consisting of cobalt, nickel, iron and mixtures thereof.
Cutting elements of the type described may be used as blanks for cutting tools, drill bits, dressing tools and wear parts.
The method for manufacturing such cutting elements has been described in U.S. Pat. Nos. 3,745,623, 3,743,489 and 4,525,179 and such descriptions are incorporated herein by reference.
U.S. Pat. No. 4,525,179 also describes a method for producing a plurality of cutting elements from a single pressed mass by placing partitions within the crystal mass before BP/HT processing. These partitions are later removed by acid leaching to obtain the plurality of small cutting elements.
It has also been the practice in the industry to wire cut the pressed mass to separate the mass into a plurality of small cutting elements. However, the mass itself and the resulting cutting elements were simple shapes having flat diamond surfaces.